Comparative Effectiveness Research (CER) compares benefits and risks of different treatments. However, little is known about the impact of large-scale CER implementation as conceived in the 2010 Affordable Care Act (ACA) on equity in health care across racial/ethnic groups. Identifying the influence of FDA risk warnings on disparities in psychotropic drug use provides a platform to understand how CER will influence disparities in certain situations. Disparity methods have typically not taken into account specific recommendations and warnings on effectiveness and safety. With the advent of the ACA and continued concern over persistent disparities, it is imperative that disparities research continues to evolve to incorporate lessons learned from CER. We capitalize upon time trends in warnings and advisories to understand disparities in diffusion with the intention of identifying policies tht might avert the negative equity consequences of incorporating CER into routine practice. Specifically, we 1) Track changes in antidepressant use among youth and antipsychotic drug use among youth and adults by racial/ethnic group as they are influenced by CER-generated risk warnings and advisories; 2) Assess whether specific information in FDA warnings influenced disparity trends in a) treatments recommended by CER-generated evidence (e.g., fluoxetine use and metabolic screening for antipsychotic users); and b) psychotropic drug use that is potentially harmful (e.g., olanzapine use); and 3) Identify how provider characteristics an HMO enrollment act as mechanisms that underlie the differential diffusion of CER via health risk warnings. We implement the Institute of Medicine (IOM) definition of healthcare disparities in order to capture trends in disparities over time, overlaying timelines of warnings and recommendations related to antidepressant and antipsychotic drugs. We adapt IOM methods by decomposing disparities in overall drug use into disparities in specific categories of use mentioned by FDA warnings as carrying particular risk or benefit. If we find racial/ethnic disparities in diffusion of risk warnings and advisories, this suggests policymakers should focus on improving uptake of CER among minorities. If we identify that certain providers and HMO membership influences disparities in diffusion, this will lead to recommendations for policymakers of actionable policies to avert the negative equity consequences of incorporating CER into routine practice.